Electric switch



May 16, 1933.l

H. A. DOUGLAS 1,909,664

ELECTRIC SWITCH Filed Nov. 11. 1931 Patented May 16, 1933 PATENTI OFFICE r HARRY A. DOUGLAIS, F BRQNSON, MICHIGAN ELECTRIC SWITCH i lpplication led November 11, 1931. Serial No. 574,272.

This invention relates 'tofelectric' switches and has for its general object the simplification of the structure and operation thereof.

. end wall 2 and adapted to fall into a small ho'le 7 in the mounting.

In the present embodiment of the invention Among other objects, the invention aims to the sleeve 3 provides a bearing for one memprovide an improved rotary switch which is of particular utility as a rheostat for controlling the iiow of electric current to a current consuming device such as the motor of a fan for an automobile heater. c

1 The invention will be more fully explained in connection with the accompanying drawin in which- Y Figure 1 is a longitudinal elevational view of a preferred embodiment of the invention; Figure 2 is an end view of the structure of Fi ure 1; l

igure 3 is a longitudinal sectional view of the structure of Figure 1 being a section taken on the line 3-3 of Figure 2;

v Figure 4 is a cross section taken on the line 4-4 of Figure 3 looking in one direction 5 Figure 5 is a cross section taken on the line 5-5 of Figure 3 looking in the opposite d1- rection; and l Figure X6 is a perspective v1ew of some of the elements in separated relation. l Referring in detail to the iguresof the drawing, I have shown a switch casing for my improved switch here represented by the cylindrical metallic cup-shaped casing `1 which has an integral end wall 2 angular to the body of the casing and in a central aperf ture of which end wall is riveted a sleeve 3.

The sleeve 3 is desirably exteriorly threaded to have screwed thereon a retaining ring 4.

The casing is advantageously located on a `mounting 5 which in one specific use that I now contemplate may be the dash board of o an automobile. The switch is secured to the mounting by passing lthe sleeve 3 through a suitable aperture in the mounting and clamping the portion of the mounting surrounding the aperture between the end wall 2 of the casing and the retaining 'ring 4 the latter being shown knurled around its periphery to facilitate tightening. To further insure that the switch casing will occupy only one rotative position with respect. to the mounting,

. '50 I provide a lug 6 struck outwardly from the ber of a rotor, in this instance, the metallic shaft 8 which is journaled in the sleeve and is adapted to freely rotate therein. For convenience in rotating the shaft 8, I have shown a handle 9 connected therewith as by being screwed into a transverse hole passing through the outer end of the shaft. Such handle permits the shaft to be readily assembled with the sleeve 8 by being passed throu h the interior of the casing 1 with the han e,

removed and` thereafter the handle located 'C5 in position as shown.

The rotor for the switch is inclusive of an insulating member represented in this instance by the floating fiber block 10 which isy keyed to the shaft 8. The shaft 8 has an en#A 70 larged head 11 with a key way 12 cut transversely thereof to receive the ber block 10. The head 11 prevents movement ofthe shaft outwardly of the casing. The shaft 8 i`s. also desirably hollow and contains therein the 'l coil spring 13 which presses the fiber block 10 outwardly of the key wayr 12, but is prevented by means later described fromdisengaging the fiber blockffron'i the key way. Thus the benblock 10 has resilient movement in the key way longitudinal of the shaft 8. To enhance the action of the spring 13, the ber block 10 desirably has a short tail portion 14 which enters the hollow shaft 8 beyond the key way 12vand engages the spring 85 13 to compress theV spring when the block and shaft are held in interengaging position.

Upon its side opposite the tail portion 14 the fiber block 10 has a reduced key portion 15 o which enters a similarly shaped slot 16 in a J y metallic switch member 17. The switch member 17, insulating block 10 and shaft 8 are thus keyed to rotate together and the switch member is insulated from the shaft. To 10595 cate these parts in assembled position, the portion 15 of 'the block 10 passing through the slot in the switch member is continued in a further reduced portion 18 which is jour-L naled in a central circular aperture 19 of a' closure for the switch casing here shown as the insulating disc 20. The disc 20 may be secured to the casing as by having prongs 21 of the casing clinched over the dlsc.

5 In the illustrative construction, the insulating disc 20 constitutes a contact carrier for a plurality .of .fixed circumferentially disposed metallic contact members mounted thereon and which are adapted to be selecl tively engaged by the switch member y17, means being provided for maintaining the switch member in continuous ,en agement with one'of the contact members. uch con.- tact members are typified at 22, 23, 24, 25 and 26, each of these terminating within the casing in a dome shaped contact surface 27 ada ted 4to seat in a depression 28' in the face of tiie switch member 17. One of the contact members, in this instance, the member 22 rivets to the insulating disc 20 a metallic plate 29 which has a ring shaped portion 30 margining the aperture 19 in the lnsulating disc 20, the inner periphery of the ring being advantageously continued to form a lip 95 30* which provides a bearing surface for the continuation 18 of the block 10. The ring 30 thus constitutes a central continuation of the Contact 22 andthe contacts 23, 24, 25, and 26 are complementary thereto.

In accordance with this exemplification of my invention, the switch member 17 is provided with two contact portions, one of these portions being represented here by an angular toe 31 which rides on the ring portion 30 of the plate 29 and the other contact portion by the portion of the switch member containing the depression 28. The toe 31 serves the double purpose of maintaining the switch member 17 in continuous electrical engage- 40 ment with the contact member 22 and at the same time provides a fulcrum upon which through the action of the spring 13 the switch member is pressed into engagement with the central contact and with one of the complementary contact members 23, 24, 25 or 26, when the shaft 8 is appropriately rotated, the de ression 28 contributing to a snap action o the switch.

The toe piece 31 terminates ina flat surface 31 of substantial pro ortions transversely of the switch member 1g switch member substantially perpendicular to the contact members so as to afford good electrical connection with the plate 30 and also to maintain the switch member substantially parallel with the plate to prevent it from dropping between the contacts. The switch member 17 is desirably flared at its outer end to form a segmental portion 17 embracing a substantial arc of the circle traveled by the switch member, so that the switch member will readily ride from one contact member onto the next. Curved cam surfaces 17b are provided at the ends of the segmental 05 portion 17* to facilitate this riding action cordance with well known so as to maintain the of the switch member. Since, as shown, the -key portion 15 of the block is elongated transversely of the switch member 17, the switch member may oscillate slightly on an axis which is transverse to the shaft 8 and which passes between the depression 28 and the toe 31 to insure that the switch member will contact with both the plate 30 and the selected complementary contact.

The Contact member 22 may be connected, by means of the binding screw 32, with a conductor leading to a suitable source of electric current. When the shaft 8 is turned to bring the switch member 17 into rotative position such that not only is the toe 31 in contact with the ring 30 but also the contact member 22 is seated in the depression 28 of I the switch member, then the switch is in off position, no electrical connection being then made between the contact 22 and any of the other contacts.

It is desirable that the shaft 8 may be rotated in only one direction from the position last described and to accomplish this I have shown a stop 33 against which a finger continuation 34 of the fiber block 10 abuts, as best shown in Figure 5.- The shaft 8 may be then rotated, however, to electrically connect the contact 22 through the plate 29 with the contact 23. The contact 23 may have connected thereto, by `means of one of the binding screws 32, a conductor leading to a motor (not shown) where the invention is employed to control the speed of a fan. With the contact members 22 and 23 thus electrically connected by the switch member 17, the fan will operate at full speed in acprinciples of operation of such devices.

When it is desired to reduce the speed of of the fan, the shaft 8 may be turned to cause the switch member 17 to electrically connect the contact member 22 and the contact member 24. The contacts 24, 25 and 26 are connected with the contact 23 through an element such as the high resistance Wire 35, the contacts 24, 25 and 26 tappin successively a greater number of turns of t e resistance so as to increase the resistance of the circuit through the motor as the switch member 17 may be placed in contact successivel with the contact members 24, 25 and 26. When the switch member 17 is in engagement with the contact member 26, the finger 34 of the block 10 then abuts the sto 36 which prevents the switch member from being further rotated in its last direction of rotation. Thus the switch cannot be turned directly from the off position to include the resistance 35 in circuit.

The stops 33 and 36 may be conveniently formed by being struck out of the body of the casing 1.

Having described one embodiment of my invention, I claim:

1. In an electric switch, the combination of a casing; a hollow metallic shaft journaled in one end of the casin a ber block keyed to rotate with the sha t and movable longitudinally thereof; a coil spring housed by'the shaft and pressing the ber block `longitudinally of the shaft; a metallic switch member fulcrumed on said ber block and keyed to rotate therewith; an insulating disc forming a closure for the casing at its end opposite the shaft; a central aperture in said disc; a continuation of the ber block journaled in saidaperture; an annular metallic contact' marginin'g said aperture; a toe on said switch member engaging said annular contact in all positions of the switch member; and complementary contacts radially disposed on said disc and selectively engageable by the switch member upon rotation by the shaft. j

2. In an electric switch, the combination oa casing; a sleeve xed in one end of the casing; a hollow metallic shaft journaled in said sleeve; an enlarged head on said shaft within the casing and abutting said sleeve;

'a transverse keyway in said head; a rectangular ber block disposed transversely of the shaft in said keyway, said block havinga tail portion extending into the bore of said shaft; a coil spring housed in said shaft and pressing upon the tail portion; a rectangular key portion on said vblock oppositely disposed from said tail portion; a metallic switch f member disposed transversely of said block and having a rectangular slot therein snugly receiving said .key portion of the block therethrough, said switch member having an angular Ytoe closely adjacent said slot upon one side of the block and being flared at its end upon the other side of the block'to form a segmental portion farther removed from the block than the said toe; an. insulating disc forming a closure for the casing at its end opposite the sleeve; a central aperture in said disc; a continuation of the ber block journaled in said aperture;

an annular metallic contact marginlng said aperture and engage'able by said toe in all positions ofthe switch member and complementary contacts radially disposed on said disc and selectivelyengageable by the segmental portion of the swltch member upon rotation by the shaft.

In witness whereof, I hereunto subscribe my name.` p

HARRY A. DOUGLAS. 

